Disseminated mycobacteriosis can result in pancytopenia and marrow hypoplasia or aplasia.
This can occur with either M. tuberculosis or one of the atypical mycobacteria.
Histologic features of a mycobacterial infection:
(1) granulomas
(2) fibrosis
(3) hemophagocytosis
(4) marrow necrosis
(5) foamy macrophages
The presence of acid fast bacilli is diagnostic:
(1) The number of organisms may be very low, so routine stains may show false negative results.
(2) Culture is useful if positive but may take some time.
(3). A molecular amplification test may be more sensitive and is quicker than culture.
Other factors to consider:
(1) history of mycobacterial exposure or infection
(2) positive response to antimycobacterial therapy
(3) exclusion of other causes
